Bead Chain Gear
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Published on December 16, 2012
Description
A gear design for steel bead chains that you might find on a window blind or light fixture.
Instructions
This gear design fits beaded chains where the diameter of the bead is 4.5mm and the link length (aka distance between beads) is (roughly) 1.5mm.
The gear's inner diameter is 5.5mm, and its outer radius is 20.1 mm. There are 21 teeth. Each tooth is a half sphere (actually, it's a hull) meant to fit at least half of the bead.
I recommend the larger zaxis hull design because it is a little more forgiving to minor deformities in the gear or beads and catches the beads better. The stl file "with sides" uses the zaxis hull design by default.
If you print this on a 3d printer, I highly recommend setting the fill pattern to concentric circles, unless you have a good printer whose y axis can vibrate back and forth very quickly, or you set the speed to something dreadfully low.
To generate this stl file yourself, you can checkout my attached openscad code. The latest version of the code exists here:
github.com/adgaudio/3dPrinter/blob/master/bead_chain_drivetrain_system.scad
To find your own dimensions for a gear of different make, you can use this script:
github.com/adgaudio/3dPrinter/blob/master/gear.py
The gear's inner diameter is 5.5mm, and its outer radius is 20.1 mm. There are 21 teeth. Each tooth is a half sphere (actually, it's a hull) meant to fit at least half of the bead.
I recommend the larger zaxis hull design because it is a little more forgiving to minor deformities in the gear or beads and catches the beads better. The stl file "with sides" uses the zaxis hull design by default.
If you print this on a 3d printer, I highly recommend setting the fill pattern to concentric circles, unless you have a good printer whose y axis can vibrate back and forth very quickly, or you set the speed to something dreadfully low.
To generate this stl file yourself, you can checkout my attached openscad code. The latest version of the code exists here:
github.com/adgaudio/3dPrinter/blob/master/bead_chain_drivetrain_system.scad
To find your own dimensions for a gear of different make, you can use this script:
github.com/adgaudio/3dPrinter/blob/master/gear.py
You must be logged in to post a comment.
Dalton11
on
December 16, 2012
said:
Will it work with Christmas beads?
adgaudio
on
December 16, 2012
said:
I'm not sure - what are Christmas beads? If you have a caliper, you could measure the bead diameter and the link length to see if it might fit in this gear. You can always change the scale... Or just print it!
There's also this beaded belt gear which may fit other shapes a little better due to its teeth design, though you'd need an m8 nut and threaded rod:
http://www.thingiverse.com/thi...
License
Bead Chain Gear by adgaudio is licensed under the Attribution - Share Alike - Creative Commons license.

This also looks like a very similar creation: http://www.thingiverse.com/thi...